Multiple realities
(covers information from several alternate timelines)

Ronnie Knox was a Starfleet officer.

In 2372, he was named as a Research and Development officer on the dedication plaque on the USS Valiant. (DS9: "Valiant", dedication plaque)

In an unknown, alternate future timeframe, he was named as a Fleet Ops officer on the dedication plaque of the USS Pasteur. (TNG: "All Good Things..." dedication plaque)

This character was only mentioned in writing.
He was named after chief lighting technician R.D. Knox.
Retroactive continuity: In 2328, Knox boarded the transport ship SS Manila at Coopersworld bound to Johnson Station. This information of the passenger manifest was recorded in the commercial transport database and reviewed by Lieutenant Commander Data in 2370. (TNG: "Inheritance")